The goal of the present article is to empirically assess the determinants of EU jurisdiction on merger cases. To this end, we employ a dataset of 655 merger cases, which the EU Commission investigated as to their compatibility with the common market between 1990 to 2002. We linked these cases to a database providing us with exhaustive data on the structural framework of the mergers. According to the binary nature of the Commission's decision (clear, remedy) we employ a probit model to estimate the determinants for an intervention and differentiate between phase 1 and phase 2 effects. Based on five hypotheses, we construct and estimate five different econometric models. We interpret the results and compare them to the relevant literature. Finally, the most statistically significant results are merged into a joint model.